[1] Univ Tennessee, Div Pediat Surg, Pediat Surg Sect, Hlth Sci Ctr, Memphis, TN 38105 USA
[2] Univ Texas, Hlth Sci Ctr, Dept Neonatol, Houston, TX USA
[3] RTI Int, Res Triangle Pk, NC USA
[4] Emory Univ, Dept Neonatol, Atlanta, GA 30322 USA
[5] Stanford Univ, Sch Med, Dept Neonatol, Palo Alto, CA 94304 USA
[6] Res Triangle Inst, Dept Neonatol, Res Triangle Pk, NC 27709 USA
[7] Univ Cincinnati, Dept Pediat, Cincinnati, OH 45221 USA
[8] NICHHD, Dept Neonatol, Ctr Res Mothers & Children, Bethesda, MD USA
[9] NICHHD, Dept Neonatol, Ctr Dev Biol & Perinatal Med, Bethesda, MD 20892 USA